A new study (yes, 500 million friends warrant a movie and a study), revealed people consider sharing Facebook info more personal than exchanging numbers. How long should we wait to "friend" a courtier? Respondents say anywhere between three dates and three months.
It makes sense to add with caution, considering how hard it is to cut an ex out of your digital life. Once you're friends, you're stuck in each others' feeds until one of you hides or de-friends the other.
Sure, there's now a nicer way to reject requests, but how long do you wait?